Mercury switch for control compasses



Oct. 3, 1950 c. H. BOLIN 2,524,340

MERCURY SWITCH FOR CONTROL COHPASSES I Filed Nov. 18, 1946 2 SheetsfSheet 1 72 INVENTOR C /eLETo/v H.501. IN

ATTOKNE YS Oct. 3, 1950 c. H. BOLIN MERCURY SWITCH FOR CONTROL COIPASSES Filed Nov. 1a, 1946 2 Sheets-Sheet 2 7 Cameron! H. 504 IN Patented Oct. 3, 1950 MERCURY SWITCH FOR CONTROL COMPASSE S Carleton H. Bolin, Seattle, Wash.; Jessie R. Bolin cxecutrix of said Carleton H. Bolin, deceased Application November 18, 1946, Serial N 0. 710,535

1 Claim. (01. 200152) This invention relates to compass controlled systems and circuits and more particularly to improvements in control compasses designed for use in connection with electrical systems, for example, systems of that character used for the automatic steering of ships as disclosed in my co-pending application filed on- July 19, 1945, under Serial No. 605,992, wherein a ships rudder is controlled in its steering function by a powcred mechanism which, in turn, is controlled through electrical devices to which current is supp-lied under control of a compass.

It is the principal object of this invention to provide improved means whereby electrical current may be supplied under compass control for the energization of electrically operated devices.

More specifically stated, the object of the present invention is to provide novel and practical means adapted to be used in combination with the cover plateand compass card of a compass for making and breaking-an electric circuit incident to oscillating action of the cover plate relative to the compass card.

It is also an object of the invention to provide circuit contacts of novel kind for use in control compasses of the kind above stated, that will minimize to the utmost degree any influence on the compass card in making or breaking a contact;

Still further objects of my invention reside in the details of construction of a mercury contact element and a contactor therefor, and in their relationship and mode of use as will hereinafter be fully described.

In accomplishing these and other objects of the invention, I have provided the improved de tails of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein:

Fig. 1 is a plan viewof a compass of typical form as equipped with contacts and contact actuating means inaccordance with the present invention.

Fig. 2 is a horizontal, sectional view of the same.

Fig. 3 is an enlarged sectional view of the mercury contact members characterized by this invention.

Fig. 4 is a, cross-sectiontaken on line 4 in Fig- 3.

Fig. 5 is a planview of a compass with an alternative form of contactmounting means.

Fig. 6 is an ,elevationalview of parts, showing the relationship of the contacts to each other and all) to the actuator cam fixed on the pivot bearing-of the compass card,

Fig. 7 is a diagrammatic illustration of a con trol system with which the present compass con trolled contacts are used.

For a better understanding of the mode of operation and use of the present compass control system and the novel contacts, it will here beexplained that one use to which these parts-may be applied would be that of the pilot compass .and system disclosed in my co-pending application, previously mentioned, wherein I have described an automatic steering system for rudder equipped water craft. In accordance with the disclosures of that application, the ships rudder is continuously oscillated in a comparatively short arc-of travel by a reversible power means operating under control of the pilot compass; the compass, in turn, being oscillated in accordance with the rudder action, and by the rudder through .circuit contacts carriedonthe compass card and plate that are engaged and dis-engaged by said relative movements, to effect the alternate energization and de-energization of an electrical control unit for the power device to reversely actuate the latter and thus to impart the oscillating motion to the rudder.

One of the special requirements for most-sat isfactory use of the present type of compass con trol system is that the functional engaging and disingaging of the circuit contacts shall not have any particular eiiect on compass card action and that the action of the compass shall not impair the utility of the delicate contact control members; therefore it is in respect to these requirements that the present improvements have been particularly directed.

Referring first to Fig. 7 in which I have, for purpose of better explaining the use and mode of operation of the compass, diagrammatically illustrated certain electrical devices as assembled in a control system for which a compass equipped with the present invention is adapted to be used, It) designates, in its entirety, a control compass; II av relay and I2 a battery or other suitable source of electricity. Leading from opposite poles of the battery [2 are wires l3 and M, the wire l3 leading to one side of the relay coil andthe wire M to a binding post l5 whichis mounted on the'compass cover plate as shown in Fig;v l. or 5. Also, there is a circuit wire l6 leading from the other side of the relay coil to a bindin post I I mounted on the compass cover plate. The electrical contacts which are featured in this-in.- vention are supported by the two bindingzposts circuit of much greater value, and r l and I1 for adjustment thereby, and are electrically joined thereto, and these contacts are designated in Fig. 7, generally, by the reference numerals l5 and and, as will presently be more full explained, are adapted to be moved relative to each other to make and break a relay circuit by means on the compass card.

The making and breaking of the relay circuit. by the engaging and disengaging of the contacts l9 and 29, is for the purpose of energizing a solenoid for the actuation of a reversing switch 22 which controls the operation of electrical devices not herein shown or described, whereby the oscillatory action of the ships rudder is efiected.

As here shown, the switch 22 comprises a mercury tube 23 fixed on one end of a horizontally directed, vertically oscillating lever The lever is pivoted between its ends on a support 25 and at its other end is operatively connected as at 25 with the armature 2? of a solenoid which is designated in its entirety by numeral 28. The solenoid has one terminal connected to a battery 38 or other suitable source of electricity, by a circuit wire and a wire 32 connects the other pole of the battery with a contact 34 of the relay H. Also, a wire 35 leads from the other terminal of the solenoid to the relay armature 35 which is adapted to make and break contact with the contact member thus to energize or de-energize the solenoid. Upon the solenoid being energized, the lever will be moved to reverse the position of switch 22.

Through the above described arrangement of parts, it will be understood that a current oi very small value, for example of the order of .063 ampere, can be utilized to control the relay H, and this may be utilized to control a solenoid is in turn to actuate the reversing switch. contacts l9 and for controlling the of these circuits must be of such kind as not to require any appreciable effort on the part of the compass to bring them into and from circuit controlling contact. These contacts will be described more particularly with reference to the showing of parts in Figs. 1 to 4.

In Figs. 1 and 2, 59 designates the housing of a typical form of compass, having a glass cover plate 5| mounted thereon in suitable manner. The compass card is designated at 52 and is supported by a pivot stud 53 that is fixed vertically in the housing. As noted in Fig. 2, the pivot stud extends into the jewel case 5t, or pivot housing, which is fixed to and extends upwardly from the card at its axial center.

In Fig. 1 it is shown that the binding posts l5 and ll, previously mentioned, extend through the cover plate substantially at diametrically opposite sides, and at their upper ends these posts are connected respectively to the circuit wires 1-: and [6.

At its lower end, the post l5 has a flat head portion and soldered thereto is a very fine circuit wire 5i that extends from the post l5 over the top of card 52, close to and slightly be yond the jewel case 54, as best shown in Fig. 2. Likewise, the binding post I! has a flattened head portion at its inner end to which one end of a wire 56 is soldered, and which wire, at its other end is soldered to the top portion of a small horizontally disposed barrel 68 formed from an electrically conductive metal and having an axial bore 68 therein of small diameter containing a quantity of mercury designated in Fig. 3 by numeral 10.

At one end, the bore 69 is closed, but at its other end it is counterbored as at H and is fitted with a fiber closure plug 12 which has an axial bore 13 therethrough which is designed to freely contain therein, as noted in Fig. 3, and end portion 6| of the wire 5|; this end portion being bent at a right angle to the wire.

The mercury containing barrel 68 is so supported that the end portion 6! of the wire 61 may be moved endwise in the bore 73 and thus brought directly into and from contact with the mercury 10. This relative movement of the wire BI and barrel is here accomplished by means of a cam member 83, or arm that extends radially from the side of the jewel case 54 of the compass card, and in such relationship to the wire 6! that by the oscillating of the compass housing through a predetermined arc, the cam will be engaged with the wire and so move it, with each reversal in direction of oscillation, to break the circuit connection between the mercury i6 and part 51 For an exact determination of the position of the barrel, so that the end portion El 01 wire may at all times be axially centered in the passage 13, I provide a second support for the barrel. This comprises a post or screw that is fixed in the cover plate at about a 90 interval relative to the post ii and this has a wire 9! fixed at one end to the post head and soldered at its other end to the barrel as at 92 in Fig. 3.

The wires 66 and 91 each are formed with a right angle bend and loop, to give certain fiexibility of movement thereto, and it is thus possible, by making rotative adjustment of the supporting posts H and 98, to make those necessary slight movements of the barrel with exactness and also to shift it endwise to an extent sufhcient to make whatever adjustments between mercury and wire 6 I that are necessary.

To impart a better understanding of the nature of the invention, it will here be mentioned that in installations now made, the wire 5! has a diameter of .005" and the hole 13 has a diameter of .040, and a good circuit connection is made by merely contacting the inner end of wire 6| with the mercury ID.

The design of the metal barrel, preferably of bronze, and mercury chamber or bore 69 is such that the mercury is held in place in the bore 69 by induced capillary action and retained against loss by the plug 72, which acts also as a guide for the wire El, keeping it centrally located in bore 59. The mercury, in this instance, is made to adhere to the bore 69 of the barrel with capillary action by first washing the walls of the bore with nitric acid.

In the alternative form illustrated in Figs. 5 and 6, the mercury containing barrel 58a is supported from post H by a straight length of wire 95 and the contact wire Gla, which corresponds to wire 6! of the device of Fig. 1, is formed in a U-shaped bend. It is secured at one end to the post 15 and its loop portion eX- tends beyond the center of the compass card, with its other leg portion passing adjacent the jewel case 54 for actuation by the arm 8| which extends radially from the jewel case in the same manner as previously explained in connection with the actuation of contact wire 6 I.

At its free end, the wire Gla has a contact portion Gib turned at right angle for entering the barrel 68a which is constructed like the barrel 68 in Fig. 3, and circuit contact is made between the mercury therein and wire Gib in a manner as previously explained.

Having thus described my invention, what I claim as new therein and desire to secure by Letters Patent is:

In combination, a rotary movable cam element, an electric circuit and contact elements connected therein for controlling flow of current in the said circuit; one of said contact elements comprising a body of electrically conductive metal formed with a capillary bore open at one end, a mercury column retained in the said bore by capillary attraction and the other of said contact elements comprising a resilient circuit wire of substantial length fixed at one end engaged and flexed by said cam in its rotating action and having its opposite end portion turned at a right angle and extended directly into the open end of said bore into circuit closing contact with the said mercury column; said cam being arranged to contact said resilient wire for moving the said end portion of the wire from contact with the mercury column; said bore of the mercury containing body being counterbored 6 at its open end, a closure plug fitted in the outer portion of the counterbore leaving its inner portion open as a reservoir for mercury spilled from the bore, and having a small diameter bore therethrough through which the end portion of the wire extends with clearance for its functional movements.

CARLETON H. BOLIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 901,331 Everett Oct. 20, 1908 2,068,065 Neubert Jan. 19, 1937 2,325,785 McCabe Aug. 3, 1943 FOREIGN PATENTS Number Country Date 247,686 Germany June 5, 1912 

